The invention relates to a detent fitting for locking two vehicle parts according to the preamble of claim 1.
A detent fitting of this kind comprises a first fitting part, a second fitting part mounted rotatably about a rotation axis with respect to the first fitting part and three locking pawls mounted movably on the first fitting part. The locking pawls are designed and provided to be brought into engagement with a toothing of the second fitting part for locking the first fitting part with the second fitting part and to be brought out of engagement with the toothing of the second fitting part for releasing the locking.
Such a detent fitting can for example serve, in a vehicle seat, for locking a backrest relative to a seat part and hold, in the locked state, the backrest in position with respect to the seat part. Through releasing the locking the backrest, then, is released such that the backrest can be moved with respect to the seat part to for example adjust the position of the backrest or to pivot the backrest forward and to thereby increase the loading space behind the backrest or to allow a passenger to enter a seat bench behind the backrest.
To pivot a backrest in a defined way into a fold-forward position usual detent fittings provide so called free-pivoting ranges in which the locking pawls of the detent fitting cannot come into engagement with the toothing on the second fitting part. For this, on the second fitting part free-pivoting sections are formed which each are associated with a locking pawl and cooperate, when turning the second fitting part relative to the first fitting part for example while pivoting a backrest, with the locking pawls in such a way that in the free-pivoting range (which corresponds to a predefined angular range on the pivoting path of the detent fitting) an engagement of the locking pawls with the toothing of the second fitting part is prevented.
In a detent fitting known from DE 10 2006 000 523 A1 three locking pawls mounted on a first fitting part cooperate with a guiding contour being formed in a second fitting part which comprises three free-pivoting sections protruding radially inwards. In that in the free-pivoting ranges protrusions mounted on the locking pawls enter the angular range of the free-pivoting sections, the locking pawls, in the free-pivoting ranges, are held in a position displaced radially inwards and in this way cannot come into engagement with a toothing on the second fitting part. In this way, a locking of the detent fitting is prevented in the free-pivoting ranges.
In a detent fitting comprising three locking pawls the three locking pawls are mounted equally spaced on the first fitting part and, consequently, are displaced with respect to each other by 120° about the rotational axis. If a guiding contour which extends about an angle and comprises a free-pivoting section is associated with each locking pawl, a pivoting range results which is limited in that the free-pivoting sections on the second fitting part must be periodically repeated. The pivoting range of the detent fitting that can be achieved, thus, is limited. In particular, the detent fitting can be pivoted by a maximum of 120° until the locking pawls run into the guiding contour of the respective adjoining locking pawl, because the guiding contours repeat themselves periodically with an angular distance of 120°.
Form DE 102 178 73 B4 a detent fitting is known in which only one of the three locking pawls is designed to cooperate with a free-pivoting section. No free-pivoting sections are associated with the other two locking pawls such that these, when pivoting the detent fitting, are not additionally prevented from lockingly engaging with the toothing of the second fitting part. In this way, on the one hand a larger pivoting range of the detent fitting can be achieved. At the same time, however, when pivoting the detent fitting there exists the risk that the locking pawls come into contact with the toothing of the second fitting part and, hence, prevent the pivoting or at least hinder it and, possibly, lead to a damaging of the detent fitting.
From DE 10 2006 015 560 B3 a detent fitting with four locking pawls is known, two of which interact with two guiding contours lying opposite to each other in a radially outer position and two of which interact with guiding contours lying opposite to each other in a radially inner position in a pairwise fashion for preventing an engagement in a pre-pivoting range. The constructive configuration of such a detent fitting comprising four locking pawls differs substantially from the one of a detent fitting comprising three locking pawls. In a detent fitting comprising three locking pawls a pairwise arrangement of locking pawls and a provision of guiding contours with free-pivoting sections lying opposite to each other is not possible.